1. Field of Invention
The present invention generally relates to a wavelength dispersion device, more particularly to an optical wavelength dispersion device in a SoC (system on chip) for reducing the size and cost of the device.
2. Description of Related Arts
Optical communication is any form of telecommunication that uses light as the transmission medium. An optical communication system consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. The receiver comprises an input slit for receiving the optical signal, and a grating for splitting and diffracting the optical signal in different directions for outputting. In other optical applications, such as spectrometers or optical analyzers, the grating plays an important role in the applications.
By far, leading technology for manufacturing MEMS devices is Si-micromachining and its various derivatives. However, many applications of microsystems have requirements on materials basis, geometry, aspect ratio, dimensions, shape, accuracy of microstructures, and number of parts that cannot be fulfilled easily by mainstream silicon-based micromachining technologies. LIGA, an alternative microfabrication process combining lithography, electro-plating and molding, enables the high precision manufacture of microstructures with large structural height ranging from hundreds to thousands of micrometers thick. The yield of de-molding process in LIGA is not high enough for fabricating vertical grating due to the small pitches of grating structure.
U.S. Pat. No. 7,034,935 discloses a high performance miniature spectrometer with a detector array optically coupled to a slab waveguide structure, and a focal plane provided outside of the output face of the slab waveguide structure. The detector array is mounted onto the slab waveguide structure at a fixed distance from the output face on the output focal plane. Obviously, the size of the spectrometer in the U.S. Pat. No. 7,034,935 is not effective because the structure of the spectrometer is assembled by a plurality of elements.
U.S. Pat. No. 7,485,869 discloses an optical spectroscopy tool performed in the vacuum ultraviolet (VUV) region. However, the size of the spectroscopy in U.S. Pat. No. 7,485,869 is not effective because the structure of the spectroscopy is assembled by a plurality of elements.
U.S. Patent Application publication no. 2010053611 discloses a diffraction grating structure having ultra-high density of grooves, which comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The diffraction grating is formed by semiconductor processes. However, it is not a SoC structure.
According to the drawbacks aforementioned, the present invention provides an optical wavelength dispersion device and method of manufacturing the same for reducing the size and cost of the device.